Temperature gradient affecting mass transport in synthetic membranes

The study of mass transport induced by temperature gradients through coarsely porous membranes (effect of thermodialysis) in various aqueous solutions demonstrates that a close analogy exists with thermal diffusion in the bulk liquid phase (Soret effect). Analysis of isothermal water permeability in the same partitions shows that the state of the solution contained in the pores is not altered relative to the bulk phase to the point of making impractical an extension of the molecular theory of the Soret effect to thermodialysis. A description of the experimental results within the frame of reference of both phenomenological and molecular theory allows one to appreciate the useful complementarity of the two approaches, and yields a better understanding of the deeper meaning of the observed effects. The study of mass transport induced by temperature gradients through coarsely porous membranes (effect of thermodialysis) in various aqueous solutions demonstrates that a close analogy exists with thermal diffusion in the bulk liquid phase (Soret effect). Analysis of isothermal water permeability in the same partitions shows that the state of the solution contained in the pores is not altered relative to the bulk phase to the point of making impractical an extension of the molecular theory of the Soret effect to thermodialysis. A description of the experimental results within the frame of reference of both phenomenological and molecular theory allows one to appreciate the useful complementarity of the two approaches, and yields a better understanding of the deeper meaning of the observed effects.